1. Field of the Invention
The present invention relates to an electric junction box that can be used to make a variety of circuit connections between electric wires connected to connectors via a printed-circuit board. In particular, the present invention relates to an electric junction box that is well-suited to use in an automobile. The present invention further relates to a connection structure of a tuning-fork terminal, particularly to a structure that secures the tuning-fork terminal to an electrically connected mating terminal.
2. Description of the Related Art
Conventionally, an electric junction box, having a configuration in which connectors are mounted on a printed-circuit board and electric wires connected to the connectors are mutually connected via a conductor of the printed-circuit board, has been provided, for example, in Japanese Patent Laid-open Publication No. 2001-25137.
The electric junction box of JP 2001-25137 is configured as follows. As FIG. 12A and FIG. 12B show, assembling part 1, which uses bus bars as circuit wiring material, has opening 1a formed at the central region of assembling part 1, and terminals 2 of the bus bars are provided in a condition protruding from the peripheral edge of opening 1a. Connectors 3 are attached to the peripheral edge of assembling part 1, and control circuit board 4 is mounted in opening 1a. Terminals 5, which are provided in a condition protruding from the peripheral edge of control circuit board 4, are soldered to terminals 2 of the bus bars of assembling part 1. Electric wires connected to connectors 3 are connected via bus bars to the conductor of control circuit board 4.
In the electric junction box disclosed in JP 2001-25137, since the bus bars of assembly part 1 are disposed between connectors 3 and the conductor of control circuit board 4, the configuration of the electric junction box becomes complicated and the size of the electric junction box becomes large. And, since terminals 5 of control circuit board 4 and terminals 2 of the bus bars are soldered to each other, there are problems such as that a soldering process is required.
A conventional method for preventing disengagement of electrically connected terminals includes providing a locking mechanism directly to terminals for fixation and to provide a terminal locking mechanism inside a cavity that houses a terminal.
One example of providing a locking mechanism to terminals themselves is a junction terminal as disclosed in Japanese Patent Laid-open Publication HEI 9-102345. In this example, junction terminal 101 has receptacles 101b at upper and lower ends of base 101a and projecting hook 101c inside receptacle 101b as shown in FIG. 18. Mating tab-shaped terminal 102 has square hole 102a near the end. When tab-shaped terminal 102 is inserted into receptacle 101b of junction terminal 101, hook 101c snaps and locks into square hole 102a as square hole 102a passes over hook 101c, thereby guarding against unwanted release of tab-shaped terminal 102 from junction terminal 101.
One example of providing a locking mechanism inside a terminal housing cavity is a male terminal locking mechanism in a connector housing as disclosed in Japanese Patent Laid-open Publication HEI 7-282884. In this example, lance 108 is set to project from inside cavity 107 of housing 106 that holds male terminal 105 as shown in FIG. 19. When male terminal 105 is inserted from opening 107a of cavity 107, lance 108 locks into convex portion 105a of male terminal 105, thereby preventing male terminal 5 from disengaging from housing 106.
JP 9-102345 represents an example of inserting and connecting the tab-shaped terminal into the receptacle; JP 7-282884 represents an example of fixing the terminal into the cavity of the receptacle. Neither of the prior art documents shows, however, an example of an insertion displacement connection, where a tab-shaped terminal is press-fitted to a tuning-fork terminal. The tuning-fork terminal, instead of a female terminal that requires bending press process, is widely used these days as a terminal electrically connected to the tab-shaped terminal. The tuning-fork terminal has a crimping slot notched to receive the mating tab-shaped terminal press-fitted from the flat end of the tuning-fork terminal. The mating tab-shaped terminal is press-fitted into the crimping slot of the tuning-fork terminal with high insertion force to prevent inadvertent release of the tab-shaped terminal in normal conditions. Considering that an excessive tensile force may be exerted, however, it is preferable to provide a mechanical interlocking structure, not relying on the insertion force alone.